Power transmission



March 13, 1951 D. B. GARDINER EIAL 2,545,077

POWER TRANSMISSION Original Filed Dec. 21, 1945 4 Sheets-Sheet 1 I 34 I6 5 g 6 as 2* INVENTORS |54 .U/Nc'fi/v .5. 5552mm? END BERN/WEE L- FEHDMF/v March 13, 1951 0. a. GARDlNER ETAL POWER TRANSMISSION Original Filed Dec. 21, 1945 4 Sheets-Sheet 2 INVENTORS .UL/A/Cfi/V 5'. EH/PD/NEF mm .EEFNH/PD L- FEHUMHN Er March 13, 1951 D. B. GARDINER ET AL POWER TRANSMISSION Original Filed Dec. 21, 1945 4 Sheets-Sheet 5 1)"- mi Q "f 2 (HI DUNE/7N .5. Ema/Am? HA/D BER/W717 L. ffi'amm/ H T TURNE y March 13, 1951 D. B. GARDINER ET AL 2,545,077

' POWER TRANSMISSION Original Filed Dec. 21, 1945 4 Sheets-Sheet 4 RAPID ADVANCE CLOSED CENTER STOP DIFF. RAPID ADVANCE .2' a JD Patented Mar. 13, 1 951 POWER TRANSIVHSSION Duncan B. Gardiner, Detroit, and Bernard L. Beadman, Pontiac, Mich., assignors to Vickers Incorporated, Detroit, Mich., a corporation of Michigan Original application December 21, 1945, Serial No.

1949, Serial No. 92,932

3 Claims. 1

This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor,

The present application is a division of applicants copending application Serial No. 636,324, filed December 21, 1945, now Patent No. 2,491,371,

The invention more particularly relates tohydraulic transmission systems for driving machine tools incorporating a fluid pump, reversible fluid motor and a control panel containing the necessary valving for producing rapid advance, feed, and rapid return movements of the motor and also for stopping the same. I

In the art of hydraulic transmission systems of this type, the use of a panel incorporating the necessary valving to control the movement of the motor has become quite common. However, it has been the practice to use entirely different panels containing entirely different porting, passages, and valving to-meet the requirements of various types of installations. Thus, a panel incorporating an open-center type control valve, although suitable for some installations, would be entirely inadequate for systems demanding the use of a closed-center type of control valve or the use of a differential type control valve. For instance, whereas a panel incorporating an opencenter type control valve would be adaptable for use in a hydraulic transmission containing a constant delivery pump and reversible fluid motor for driving a single load device, if another fluid motor was added to the transmission to drive an additional load device during periods of inactivity of the first load device, an entirely different panel incorporating a closed-center control valve would have to be substituted for the first panel. b

It is therefore an object of this invention to provide a panel which may be used to fita variety of installation requirements simply by substituting a control valve of one type for a control valve of another type all of which are mountable within the same valve bore of the panel without any other changes being madeto the panel.

In particular, it is an object of this invention to vide a panel for a transmission as above stated Divided and this application May 12,

which contains porting, passages, and a valve bore designed in such a manner that three differently designed control valves may be shifted in identically the same manner within said bore for controlling the ports and passages to produce the aforementioned movements of the motor, one control valve being pf the open-center type for unloading the pump to stop the motor, another being of the closed-center type for blocking the flow of pressure fluid atthe control valve to stop the motor and the other being of the differential type to produce a differential rapid advance moveinent of the motor. 7

It is another object of this invention to provide a control panel for a hydraulic transmission system and for the purposes such as stated above which will be light in weight, compact and which will give long life and be easily convertible to suit the needs of different installations.

It is still another object to provide a panel for a system and for the purposes as above stated containing a longitudinal bore in which may be identica ly mounted any one of three I control valves of different types shiftable completely within said bore, with identical means for shiftil'lg said control valves manually or mechanically from the front or the rear of said panel by pressure fluid applied at either end of said control valve, by solenoid means, or by a combination of any of the above means. r 7

It is still another object of this invention to provide for a panel having a valve member rotatably mounted therein, such as a throttle, an improved dial and knob assembly adapted to provide coarse and fine manual operation of the valve member.

Further objects and advantages of the present invention wi l be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings: b

Figure 1 is a cross-sectional view of a panel embodying one form of the present invention taken on line ll of Figure 4.

Figure 2 is a plan view of the panel.

Figure 3 is a front elevation of the panel.

Figure 4 is a bottom view of the panel.

Figure 5 is a rear elevation of the panel.

Figure 6 is a cross sectional view taken on line 66 of Figure 3. I

Figure 7 is a diagrammatic view of a hydraulic circuit incorporating the panel of Figures 1 through 6 and showing a portion thereof in one of its different positions.

Figure 8 is a diagrammatic view of a hydraulic circuit incorporating another form of panel and showing a portion thereof in one of its positions.

Figure 9 is a view of a hydraulic circuit in corporating still another form of panel and showing a portion thereof in one of its positions.

Figure 10 is a sectional view taken along line I3I3 of Figure 2.

Referring now to Figure 1, there is shown a cross-sectional view of a unitary control panel I comprised of a block [2 having a longitudinal main valve bore I4 extending completely across said block. Bore I4 is provided with a groove forming a pressure port I6 located between two grooves forming motor ports I8 and 29. Spaced apart from port I8 is a groove forming a throttle port 22 and spaced apart from port 29 is a groove of much greater length forming a tank port 24.

aforementioned ports Pressure fluid is admitted and emitted to and from the panel I8 by means of external connection ports at the rear of said the left side of block I2 to a point of intersection with a vertical passage 36 constructed from the top of block I2 and which intersects pressure port I 6 and a passage 38 directly connected to external pressure port 32 and extending to passage 34. The exterior terminus of passages 34 and 36 are suitably closed by plugs 39. Thus,

pressure fluid entering external pressure port 32 is conducted to internal pressure port I6 by means of passage 38, lateral passage 34, and vertical passage 36. An external tank port 48 at the rear of panel Ii) is connected directly to in- .ternal tank port 24 by means of a passage 42.

Also at the rear of panel I8 is a pair of external motor ports 44 and 46. As shown in Figure 3, motor port 44 is connected to internal motor port I8 by means of a passage 48 connected directly to external port 44 which intersects a vertical passage 50 extending from the top of block I2 to a point of intersection with passage 48 and which also intersects port I8. The exterior terminus of passage 58 is closed by a suitable plug 5I. Thus, fluid entering external motor port 44 is conducted to internal motor port l8 by means of passages 48 and 50.

Motor port 46 is connected to internal motor port 29 by means of a passage 52 connected directly to port 46 which intersects a vertical passage 54 extending from the bottom of block I2 to a point of intersection with a lateral passage Passage 56 extends from the right side of block I2 to a point of intersection with a vertical passage 58 constructed from the top of block I2 and which intersects port 20. Passages 54, 56, and 58 are closed exteriorly by plugs 59. Thus, fluid entering external motor port 46 is conducted to motor port by means of passage 52, passage 54, passage 56, and passage 58.

There is shown in Figure 5 an external pilot valve port 68 which is directly connected to the left end of bore I4 by means of a passage 62 and a similar external pilot valve port 64 which is directly connected to the right end of bore l4 by means of a passage 66. There is shown in Figure 1 a longitudinal stepped passage 68 constructed completely across block I2. A vertical passage I8 and a vertical passage 12, both of which are constructed from the top of block l2, intersect both bore I4 and passage 68 at the left and right ends of said bore and passage respectively. The exterior terminus of passages 68, I0, and I2 are closed by suitable plugs I4 and, in addition, plugs I5 are inserted in passages I8 and I2 to prevent fluid in these passages from escaping through mounting holes I6 which register with said passages. These passages permit the applicationof pressure fluid to either end of the control valve for hydraulic actuation thereof and permit the control valve to shift freely within its bore by providing an outlet for discharging fluid from opposite ends of the bore when the valve is shifted.

If control valve 38 is to be hydraulically operated and pilot valve controlled, a plug I8 is inserted in passage 68 between passages I9 and I2. If control valve 30 is to be operated other than hydraulically, pl-ug I8 is removed, a suitable plug is inserted in port 62, and port 64 is left unplugged to act as a drain port for roper shifting of valve 30.

Means are provided for regulating fiuid flow by mounting an adjustable throttle 88 (Figure 6) in a stepped bore 82 extending completely through block I2 from front to rear, said bore being closed at the rear by a suitable plug 84 threaded into throttle 80. In order to maintain a constantly uniform flow of fluid through throttle 80, a pressure-responsive compensating valve 86 (Figure 1) for maintaining a constant pressure drop across throttle 80 is mounted in a longitudinal bore 88 extending completely across block I2, bore 88 being closed at both ends thereof by suitable plugs 90;

In order to connect compensating valve 86 and throttle 88 in series between external motor port 44 and throttle port 22, a vertical passage 92 is constructed from the bottom of block I2 which intersects and continues through compensating valve bore 88 to bore 82 (Figure 1). Throttle 80 is so mounted in bore 82 that a throttling portion 94 thereof (Figure 6) is in alignment with passage 92 and with a passage 96 constructed from the left side of block I2 and also connected to throttle bore 82. A passage 98 constructed from the back of block I2 intersects passage 96 and continues to a point of intersection with a passage IOI] (Figure 4) which is constructed from the top of block I2 to a point of intersection with passage 98 and which also intersects port 22. It should be noted at this point that passage 54 which is constructed from the bottom of block I2 and which extends to a point of intersection with passage 56 also intersects compensating valve bore 88 (Figure 3). Thus, if fluid entering external motor port 48 is blocked by control valve 30 at port 28, it may flow through port 46 to passage 52, from passage 52 to passage 54 and com pensating valve bore 88 and from said bore to passage 92 (Figure 1) whence it is conducted through throttle 80 and thence by means of passages 96. 98, and I08 to port 22. In order to make compensating valve 86 truly responsive to the asserts pen e ralve bore 88 a d i tersectin nassase 1-02," and a vertica passa e H18 constructed rom o m o block it ex en in t a po nt of intersection with a passage Illi- Eass e i! s Constructed from the front of block I2 to a point of intersection with passage I38 and also inter; sects valve bore 14 at port 24 (Figure 1) Referrin now o F re 1, c m ensatin val 8.6. is comprise m i o a p ston. I I2 onnec d to. which s a te H4 av lands H5. a d. Hit S em ii i s shiitable wit n a leev 1 havin por adapted o. o pe a e Wi e passa es onne d o t e com nsa va ve he s 8, Piston H2 s shii a l W hin bor 88 and is re: s ons ve. o s u n c mbe nd izi to e right d e t, res e ve y o pis on I? n or .88- le v l' coht ihs a srqq e H? which. i e s te y ass e 4 a a Pastas? '24 conne te to a d oove- Pe e 4 is $2 11.- trolled in such a manner by land I I8, grigtnally hias d t pe s n by a Spring h t he flow of fluid therefrom through another. passage I28 connected to a'groove I39 which is inter sected by passage 82 will be maintained uniformly constant. Land II8 will partially openand close 8 88 t ad i more or 3 1 f i h u h passage I28 and groove I38 to passage 82 as det i y t e ii ie e t er ure x stin n ch s I2 a d f2! an ee hg'eh qfi e sides of piston I12. Bress ure fluid is admitted to b z't e' t i t i to ts as s ls able to act against the bottom area of land H8 by means of a drilled passage I32 which is in communication with passage I28. W

' In 'ordr to maintain a pressure equal to the pressure past throttle 88 in chamber I2I, tank port 24' is connected asaforementioned to said chamber by meansof passages I88, I82; let and H8; passage I86 intersecting bore I88 at apoinft to the left of piston H2. M i

Referring now to Figures 2, 6, and 10, throttle 80 is Connected to a'dial" I38 having a raised portion I3'S'by'meansofa'bolt I38 threaded int o throttle 80, the connected'end of saidthrottle fitting into a'bore I88 of an eiitended 'p'iirt'iofildZ of said dial. Theextended portion of the dial i814 is also provided with slots MI. I! pintfiidriven through throttle 88 has end portions I inserted into' the slots MI and which extend'therefrom. The eiitreme' ends I44 of thepin I43, which ex tend frOmWhe'SIOtSYMI, are irisertable slots I 45 bra hole I46 in a cover patent? The bolt I38 prevents the dial I34 lifting from the throttle 80 While the'pin M3, in cooperation With the slots 14!, "provides a rotary drivin connectiqhbetwen' the dial I31; and the throttl al When inserting the throttle into bore 82 through theholefifi of cover plate I48, portions {54 time I43, extending from the slots Idl are inserted through the slots I85 with the extended portionsffinally abutting a shoulder I49 of bore 82; rotating the dial, which covers the hgle I46 of cover plate Hit, the complete throttle and dial assembly is held securely in place but is trely. rotatable by reason of the extended portions I44 of pin L43 being located between cover plate 6 n ho d I4 -of or '2- A leev I5I having a seal I83 is press fitted into th rear en o b 82 an he. lu 84 is threa ed into th t e .9. .0 a 9 c m lete y cl se a d seal sa he ur Referring to Figures 2 and 10, means are also provided for adjusting the throttle portion 94 within bore 82 between passages 92 and 9,6 to very clese tolerances offluid flow by connecting a sn e shaft 1. 11 byneans of a, pin 5 o a nail n -5 'o hss i e haf in eves .elii l' t' i ed n n. eiiate sl t '5 l a e s cover P ate 48 wishes .0 K -e it! s h i e'i h ide int l ts. It? ig re 2) r i h t e'i a ross ra or i i i 35. o ia 3 W r h i' qt ment of linob lfi lf, "the splined sha I58 is inounted'ina bore in r i ed paras tic b s r z ii movement eregf. The diameter of the knob H is prefer slightly. larger than the Width of raised portion "I35 fo'r teammates oftl'i'e lmob. It should benotd that the dial I6 4 may be rotated togive a is es adjustment ofthe throttle i the keel? t e stat s t i e a the thirst t of seid' h ett e For the purpose ofshifting control valve 38 ne than anal-talc finderii t i i 6i ah external Pilot al c t t t t 'i i d al e onnections 5?! an it na aiVQ -QV'iiiQ for shifting the valve at the tro n'tor rear of the an it by hav o f tafqh'e to the m or mach ne o eeii e t a r in neeetsdte rqtaiah sha t wh ch levets i fi e t9 th valve 30. As shown in Figure 1, a stepped "bore we i constr cted tem e. t l' b ee i2 i6 point of intersection with the groovetorrning port 24 ofbore I4, Another. bore lfifi is'lcbn; ct em r hmii li 19 1; 3 m m o e thereof etw t e t o aid. blea and bore I4 and which intersects bore {81. A shaft 8. shown in Figure 6 hav n am "tri ed w tit m a c ss 1H r a su able seal I76, a transverse bore I18 and a groove I88 s s rt o the ront. e blo k 12 into bore "it w h he e ".8. ofsaid s eit r t r wi the ert a bore '5 o l k Be e ri e t Figure 1 and a e I 2 ha n a at ened a M a o e end the ee is. i se t d by the medium of bore I64 into and through bore I18 of shatt I68 with ball I84 resting in a bore I86 of proportionate area located in the right end of control valve 38 The rod I82 is provided at. its end eii q t the a I8 wit threaded r 8 a s ot I f r th p p s of th eading a set screw I92 into bore I88, and, because'of slots I96 therein, slightly expanding rod I82 so that rod I82 is tightly connected to shaft I88. A was r I9 a d ck nu s. t crew I82 in place. Vertical bore I64 is closed by a suitable plug I88'having a seal 288 inserted in a recess 282 thereof which permits ample rightard and leftward shifting of rod I82.

A pin 284 (Figure 2) threaded into a bore 286 which extends from the right side of block I2 d e 6 fit t o ve ii l f shaft I 8 preventing horizontal movement thereof but leaving shaft I68 free to rotate within bore I66. A dial 208' (Figure 3) connected to shaft I68 permits manual operation of contrgl valve 30. Due to the fact that cam III) is located on shaft I68 between dial 288 and the face of panel II), suitable dogs connected to a reversible fluid motor or. to a machine tool (not shown) may easily contact tits I12. It is also possible to connect suitable c mm a e oppos e end of shaft I68 which protrudes from the rear of panel III to produce the same results.

It should be noted that control valve 30 is completely shiftable within bore I4 of block I2 by the arrangement of; having rotatable shaft I68 at right angles to control valve 38 and connecting said shaft to said valve. by means of rod I82. Thus, by rotating dial 208 or. by rotating cam I10, the rod I82 will shift valve 38 leftwardly or rightwardly depending upon clockwise or counterclockwise rotation of dial 208 or cam I10. Referring to Figure 6, as dial 288 is rotated a detent 2M backed by a spring M2 is forced into successive shallow recesses H4 in number equal to the plurality of positions of control valve 39.

In Figure 1, there is shown a control valve 30 of the open-center type shiftably mounted within bore 14. Control valve 3!] is comprised of a spool 2H3 having a groove 2"! located between an end land 2253 and a land 222, a groove 222 located between land 222 and a larger land 226, and a groove 228 located between land 226 and a land 238 of larger proportions than land 226. A longitudinal bore 232 extends from the left end of spool ZIB to a point between lands 226 and 230. Longitudinal bore 232 is in communication with a plurality of transverse ports 234 located between lands 222 and 222 and also in communication with a plurality of transverse ports 236 located between lands 226 and 238. Bore 232 is closed at its open end by a suitable plug 238.

In order to show more clearly the manner in which spool 2 I6 controls and directs the pressure fluid to and from the space-d ports along bore 1 3, control valve 32 is shown incorporated in a schematic circuit in Figure 7 and shifted to the rapid advance position. There is shown in Figure 7 a tank 248 connected to a fluid pump 2 12 by a conduit 2. The pump 222 is connected to the pressure port I6 of control valve 32 by a conduit 248. The tank port 24 of control 38 is connected to tank 243 by means of a conduit 2 33.

A reversible fiuid motor 259 containing a shiftable piston 252 to which is connected a piston rod 254 is connected from its rod end to motor port 22 by means of a conduit 256 while the piston end thereof is connected to motor port l8 by means of a conduit 258. A branch conduit 26!? connects conduit 258 to one side of the piston H2 of compensating valve 86. A conduit 252 connects compensating valve 83 and conduit 258 to throttle 8i} and a conduit 26 connects throttle 85 to motor port 22. A conduit 266 connects the opposite end of piston H2 of compensating valve 86 to tank port 24. For hydraulic actuation of control valve 35, a pilot valve 2% is connected to the right end of control valve 30 by a conduit 27!], to the left end thereof by a conduit 212, to tank 22 3 by a conduit 224 and to the pump delivery conduit 245 by a branch conduit 215. A suitable relief valve 218 is incorporated in the pump delivery conduit and is connected to tank 22:? by means of an exhaust conduit 288. For proper shifting of control valve 38, the right and left ends thereof are connected to each other by a conduit 282. A plug I8 will be inserted in conduit 282 when control valve 39 is pilot valve operated.

Referring now to Figure 7, in operation and with control valve 39 shifted completel to the left to a rapid advance position, pressure fluid will be directed from pump 222 b means of delivery conduit 246 to the pressure port I8 of control valve 39. Land 226 will block motor port 20 from port I6 and fluid is directed by means of lands 222 and 222 through the medium of groove 22% to port It and from such port to the head end of motor 258 by means of conduit 258 to shift piston 252. Discharging fluid from the rod end of motor 256 is conducted by means of conduit 258 to port 20 at which point lands 22B and 230 will, through the medium of groove 228, direct the fluid to tank port 24 from where it will be conducted to tank 240 by means of conduit 248. Due to the fact that the head end of motor 250 is in direct communication with the pump 242, and the rod or discharge end of said motor is in direct communication with tank 2 .3, the total displacement of pump 2 12 is utilized to cause a rapid advance movement of the motor.

After piston 25?. of motor 250 has been shifted a predetermined distance during rapid advance movement thereof, shaft I68 is rotated to cause spool 216 to shift to the feed forward position, not shown. In the feed forward position of valve 32 pressure fluid from pump 262 is directed by lands 222 and 225 through the medium of groove 224 to port I8 from Where it is conducted to the head end of motor 250 by means of conduit 258. Discharging fluid from the rod end of motor 258 is blocked at port 20 by land 226 and must flow to tank 240 by means of conduits 262, 262, and 264 to port 22. Discharging fluid will be regulated to a predetermined flow by throttle 82 with the cooperation of compensating valve 85 in the wellknown manner. Pressure fluid in excess of the total displacement of pump 242 reaching the head end of motor will be exhausted to tank 240 by means of relief valve 218 through exhaust conduit 289. The amount of regulated flow discharging from the motor through throttle 89 to port 22 will be direc.ed to tank 220 by means of lands 2'20 and 222 through the medium of groove 2I8 to transverse port 234, bore 232, transverse ports 235, and groove 228, from which point, lands 226 and 236 will direct the fluid through port 24 to conduit 228, the latter carrying the fluid to tank 240.

Control valve 30 being of the open-center type, if the valve is shifted to the position shown in Figure 1 pressure fluid from pump 222 is directed from port It directly to tank 240. Fluid is directed from port I5 to port l8 through the medium of lands 222 and 225 and groove 2% and from port l8 to groove 2I8, transverse port 234, bore 232, transverse port 235, groove 228, tank port 2 and conduit 223 to tank 20. It should be noted that in this position pressure port It is in direct communication with tank port 24 so that the complete delivery of pump 242 is unloaded to tank 220 in order to stop motor 252. Land 222 is designed to permit communication in this position between groove 2I8 and groove 22 through the medium of the groove forming port I8.

The ports spaced along bore I4 are so spaced apart that control valves of different form than control 38 may be shifably mounted within said bore to produce rapid advance, feed, and rapid return movements and to stop said motor. However, where it is necessary to use a closed-center control valve because of certain installation requirements, for instance, the operation of a load device from a branch line 25I in addition to motor '250 while motor 250 is stopped, a control valve corporated in a schematic circuit identica1 to that illustrated in Figure 7. A land 222 of much greater length than the corresponding land 222 of control valve 30 is spaced much closer to a left end land 228' than is land 222 from land 22!! of control valve 30. A land 226' corresponding ga an "at of rea tavern is or i '1 g'ai aesia length than land 226 and a corresponding groove is mounted and shiftable to the same positions in identically the same manner as control valve 30 except for one position thereof shown in Figures. In the stopped position fluid new from pump 2A2 entering port It will be blocked from c ommunie cation with all other ports spaced along bore I4 by m n f ands 2'and32 f- V.

When a reversible fluid motor of the cylinder and unbalanced piston type is used in the trans.-

mission, it may be desirable to have adifferential rapid advancemovement of said motor. Accordingly, a control valve of a third type may be shiftably mounted in bore I4 in identically the same manner as control valves 30 and 30', and which is illustrated in Figure 9 as being incorporated in the same schematic circuit illustrated in Figures lands.

Referring now to Figure 9, there is shown a differential control valve 30" having a groove 2 I8 between an end land 2.20" and a land 222", a groove 224 betweenland 222" and a, center land 226", a groove 221 between land 226'? and a land 229, and a groove 228" between land 229 and an end land 23!)". Control valve 3!!" is also provided with transverse port 234" between lands 220 and 222" and transverse port 236" between lands 229 and 230", said ports being in communication with each other by a longitudinal bore 232". Control valve 30" is somewhat similar to control valve 30 except for an additional center 1and 229 which forms an additional groove 221. Also, land 23B is longer in length than that of land 2311 of control valve 30. Control valve 30 will direct and control pressure fluid from pump 242 toand from the port spaced along bore I4 in exactly the same manner as control valve 30 except for the rapid advance position when it will connect the pressure port I6 to both motor ports I8 and 20 so as to provide a differential advance movement of motor I50.

It should be noted that the identical shaft I68 is connected to all three control valves in identically the same manner and that the shifting of said control valves results from the rotation of said shaft. Shaft I58 may be rotated manually from either the front or from the rear of the panel, although it can be clearly seen that the most practical method is from the front. It can also be seen that by having dogs connected to a machine tool driven by the motor contact switches, after a certain length of travel in either direction of the piston of the motor, so as to energize or deenergize one or more solenoids connected in the well-known manner to shaft I68, that several variations of combination manual and automatic shifting of the control valves are possible. I

For example, one method of shifting the control valves would be for the operator to manually shift the control valve in use to a rapid advance from the stopped position. After a certain predetermined range of travel of the machine tool, a dog connected to the machine tool would contact the cam to shift the control valve to a feed position. After a certain range of travel in the r 10 F reed position, a second dog he he plane the firstdog would contact the cam to fshiftthe control vaive to theistoppedposition. Theoperator would then manually shift the control valve to rapid reverse position and after'a certain'ran'ge of travel a third dog, on a 'difierent plane than the flrst or seconddog, would contact the cam to rotate shaft I 68 in the other direction so as to shift the control valve again to the stopped position.

Another method would be to have the eperator manually shift the control valve from the stop position to a rapid advance position and after a certain range of movement a dog connected to the machine tool would contact the cam to shift the control valve to afeed position. At the close of the feed movement, a second dog would contact a switch to energize a solenoid to shift the control valve to rapid reverse position. At the end of the rapid reverse movement, anotherdo'g would contact the cam to shift thecontrol valve to the stopped position. V

'Anothermethod would be to use an additional solenoid which would be energized atthe end of a rapid reverse movement in order'to immediately shift the control valve into rapid advance without a stop being made. The complete cycle of rapid advance, feed, and rapid reverse would be continuous :and automatic until the motor was stopped and started again manually 'by the operator.

It should be noted that a change of control valves maybe made without ohangingany of the connections or removing the panel from its mounting support simply by removing plug I98,

lock nut I96, washer I94, set screw I92, and the 7 rod I82. The control valve may then be removed from either side of the panel by removing either of the plugs 26 or 28. It should also be: noted that these elements may be removed and replaced easily for use with an alternative con-- trol valve from the front, side, and top of thepanel.

It should be further noted that both coarse and fine manual adjustment of the throttle is pro-- vided by the knob and dial assembly. The dial is fastened directly to the throttle to provide a coarse adjustment thereof while operation of the knob provides a fine adjustment of the throttle because of the gear rack in the cover plate and pinion which is connected to the knob and in mesh with the gear rack.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to beunderstood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows: I

1. A dial and knob assembly for coarse and line manual operation of a valve member adapted to be rotatably mounted within a valve block, comprising in combination a dial having a raised portion on the face thereof, and means forming a slot extending completely across the raised portion, a knob rotatably mounted in the slot of the raised portion of the dial, a cover plate provided with an arcuate gear rack, a pinion connected to the knob for rotation thereby, means for rotatably connecting the dial to the cover plate with the pinion meshing in the gear rack, means for connecting the valve member to the dial, and means for mounting the cover plate on the valve block, whereby the dial may be rotated to provide a coarse operation of the valve member and the knob may be rotated to provide a fine operation of the valve member.

2. A dial and knob assembly for coarse and fine manual operation of a valve member adapted to be rotatably mounted within a valve block, comprising in combination a dial having a raised portion on the face thereof, an extended portion opposite thereto, and means forming a slot extending completely across the raised portion, a knob rotatably mounted in the slot of the raised portion of the dial, a cover plate provided with a bore having a diameter at least equal to the diameter of the extended portion of the dial and an arcuate gear rack spaced apart therefrom, a pinion connected to the knob for rotation thereby, means for rotatably connecting the dial to the cover plate with the extended portion of the dial extending through said bore and with the pinion meshing in the gear rack, means for connecting the valve member to the dial, and means for mounting the cover plate on the valve block, whereby the dial may be rotated to provide a coarse operation of the valve member and the knob may be rotated to provide a fine operation of the valve member.

3. A dial and knob assembly for coarse and fine manual operation of a valve member adapted to be rotatably mounted within a valve block, comprising in combination a dial having a raised portion on the face thereof, an extended portion opposite thereto, a stepped bore extending completely through the dial, and raised and extended portions thereof adapted for mounting therein one end of the valve member, a second bore extending completely through the dial and raised portion thereof, and means forming a slot in the raised portion of the dial intersecting the second bore, a knob rotatably mounted in the slot of the raised portion of the dial, a cover plate provided with a bore having a diameter at least equal to the diameter of the extended portion of the dial and an arcuate gear rack spaced apart therefrom, a pinion rotatably mounted in the second bore having a portion extendin therefrom and connected to the knob for rotation thereby, means for rotatably connecting the dial to the cover plate with the extended portion of the dial extending through the bore in the cover plate and with the pinion meshing in the gear rack, means for connecting one end of the valve member adaptable for mounting in the stepped bore to the dial, and means for mounting the cover plate on the valve block, whereby the dial may be rotated to provide a coarse operation of the valve member and the knob may be rotated to provide a fine operation of the valve member.

DUNCAN B. GARDINER. BERNARD L. READMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 647,387 Evans Apr. 10, 1900 1,299,765 Norton et a1 Apr. 8, 1919 

